www.buildingsandcities.org/insights/commentaries/climate-mitigation-carbon-budgets.html

Why the built environment research community is vital for policy and strategy implementation

Thomas Lützkendorf (Karlsruhe Institute of Technology) explains how the research community has helped to change the climate change policy landscape for the construction and real estate sectors, particularly for mitigating GHG emissions. Evidence can be used to influence policy pathways and carbon budgets, and to develop detailed carbon strategies and implementation. A key challenge is to create a stronger connection between the requirements for individual buildings and the national reduction pathways for the built environment.

The UN Paris Agreement at COP21 is a legally binding international treaty on climate change that entered into force in November 2016. It defines the common goal of limiting global warming by reducing greenhouse gas emissions (GHG emissions). In response, Nationally Determined Contributions (NDCs) as well as carbon budgets for countries were established. Carbon budgets have been widely adopted, though many issues of uncertainty remain as well as issues involving the equity of distribution among countries, economic sectors and generations. At the same time, GlobalABC's status report identified that close to 40% of energy-related global GHG emissions result from the built environment, via a combination of direct, indirect and embodied GHG emissions using a cross-sectoral approach in statistics (GlobalABC 2016).

Goals, progress and conflicts

IPCC published mitigation pathways in 2018 (IPCC 2018) and several organisations and countries have developed sector-specific carbon reduction pathways, including the construction and real estate industries (UK GBC 2021; Ireland 2023). Additionally, in Germany, the Federal Constitutional Court published a landmark ruling in 2021 on the climate protection law which embedded a requirement for intergenerational justice in the carbon budget (BVerfG 2021). However, the topic is very complex. Some construction manufacturers and professionals are developing their own strategies for decarbonisation, including calling for the introduction of certification for low carbon buildings or legal binding requirements to limit GHG emissions in the life cycle of buildings. But others raise concerns about the increased costs and reduced affordability of housing. Politics, industry and society find themselves with conflicting goals. Clarity is therefore needed on the effects of climate action on society, the economy and the environment. Sustainability assessments provide useful guidance, but here too, there are two different approaches: (1) looking for appropriate requirements and measures by balancing cost-optimal solutions with climate protection (Maduta et al. 2023), and (2) calling for the general goal of climate neutrality not to be questioned and to achieve it with the least possible financial outlay (FCAA, 2019).

Research priorities

Despite progress, carbon budgets are still not universally implemented and there are important discussions to be had. For example, should budgets limit global warming to below 2.0°C or 1.5°C? How can a cross-sectoral approach in national GHG-emission statistics be achieved? And what do specific mitigation pathways look like for different economic sectors (e.g. the construction and real estate industries), areas of action (e.g. construction, maintenance and operation of buildings) and areas of needs (housing)? These issues are the focus of the ongoing International Energy Agency (IEA) Energy in Buildings and Communities (EBC) Annex 89.

Current research activity has focused on calculation and evaluation methods, and benchmarks or target values for new building designs with consideration of life cycle related GHG emissions. This has resulted in a diversity of terms, definitions, methods and requirements, as well as international and national initiatives, standardisation activities and guideline developments. While this points to an intensity of activity in creating solutions, these activities have the potential to become obstacles if they are not appropriately actioned and regularly updated, revised and harmonised.

Collaboration to achieve climate action

Individual groups of researchers have outlined many solutions to the challenges around achieving climate action in the construction and building sector, which address their own contexts as well as identifying interdependencies on other groups of actors. International collaborations, for instance the International Initiative for Sustainable Built Environment, have been relatively successful in bringing academics together to share experiences and produce collective outputs. A common goal of these collaborations has been the introduction of legally binding requirements to limit GHG emissions in the life cycle of buildings. Notable initiatives which make this case include the Graz Declaration for Climate Protection in the Built Environment which was an outcome of SBE19 and Monte Verità Declaration on a built environment within planetary boundaries (an outcome of IEA EBC Annex 72).

Achieving agreement and standardised approaches is a common theme of international cooperations. For instance, the IEA EBC Annex 72 has also provided an important contribution for the topics of calculating, evaluating and influencing greenhouse gas emissions in the life cycle of buildings. Similarly, there is work underway to achieve international standardization in methodologies to assess climate impacts via ISO TC 59 SC17 Sustainability in buildings and civil engineering works and Europe CEN TC 350. Further steps forward in regulations and guidance include the specification of GHG emissions in the life cycle of buildings in the EPBD in Europe (EU 2024), the introduction of legal requirements in France, the Netherlands and Denmark (Ramboll 2022), and existing funding programmes in Germany (KfW 2024). There are more examples from all over the world (UNFCCC 2021).

Despite all this collaboration, a gap remains between mitigation pathways (which are derived top-down from the need to comply with planetary boundaries) and the targets values and benchmarks for single buildings (which are developed bottom-up, taking into account technical and economic feasibility).

Buildings Breakthrough

At COP28 the Buildings Breakthrough initiative was launched which goes some way to addressing this gap. This initiative's overarching goal is for near-zero emissions and resilient buildings to be the new normal by 2030, and to embrace measures for mitigation and adaptation. It aims to overcome problems of conflicting priorities of nations, organisations and societies, and the resulting lack of harmony between top-down versus bottom-up activities. As with other collaborative programs it seeks consensus by involving partners from many countries, organisations and institutions. The driver is the recognition of greater reduction potential than is currently being achieved. Embedded in its approach is the embrace of the role of research, innovation and cooperation. Its core principles include the consideration of the consequences of climate change for the built environment and the importance of housing. The Buildings Breakthrough initiative incorporates a wide range of groups from governments, academia and industry, and produces outputs specifically aimed at guiding the implementation and interpretation of international agreements and influencing resulting national policies. Work will be carried out in 2025 and will be published at COP 30 arranged under 5 workstreams focussing on (1) Standards and Certifications, (2) Demand Creation, (3) Finance and Investment, (4)  Research and Deployment and (5) Capacity and Skills.

Conclusions

Researchers have provided clear evidence and guidance to assisted policymakers and practitioners to help to change the climate change policy landscape for the construction and real estate sectors. They have shown willingness to work across national borders to achieve consensus on priorities and provided policymakers with evidence to set appropriate carbon budgets, and policies for new buildings and refurbishment projects. However, more questions still need to be answered, and more effective implementation is needed to make carbon budgets a reality for countries, cities, neighbourhoods, individual buildings, and it is probably that legal binding requirements will be needed. Additionally, current successes have not achieved the changes needed and the level of urgency to make these changes is getting higher every day.

The built environment research community needs to improve the way evidence is being used to influence policy pathways and carbon budgets, and detailed carbon strategies and implementation. To achieve this, a stronger connection between the requirements for individual buildings and the national reduction pathways for the built environment is needed.

The research community should have a greater role in explaining concepts around carbon budgets and net zero GHG-emission targets to practitioners and wider civil society. It will be important to improve and expand the use of sustainability assessments in decision making and expand the range of impacts that are considered and international efforts to standardise approaches to assessing GHG emissions, biogenic carbon, the use of primary raw materials, climate resilience, thermal comfort are important steps in achieving this. Through continued collective efforts, researchers can and will help to accelerate the acceptance and implementation of next generation of strategies for a sustainable built environment. International agreements build the foundation and the next big challenge is global implementation.

References

BVerfG. (2021). Beschluss des Ersten Senats vom 24. März 2021- 1 BvR 2656/18 -, Rn. 1-270. Deutsches Bundesverfassungsgericht. https://www.bverfg.de/e/rs20210324_1bvr265618.html

EU. (2024). Directive (2024/1275 of the European Parliament and of the Council of 24 April 2024 on the energy performance of buildings (recast). European Union. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32024L1275

FCAA. (2019). Federal Climate Action Act of 12 December 2019 (Federal Law Gazette I, p. 2513) in Germany. https://www.gesetze-im-internet.de/englisch_ksg/englisch_ksg.html

GlobalABC. (2016). Towards zero emission, efficient and resilient buildings: Global Status Report 2016, Global Alliance for Buildings and Construction. https://globalabc.org/sites/default/files/2020-03/GABC_GSR_2016.pdf

IPCC. (2018). Mitigation Pathways Compatible with 1.5°C in the Context of Sustainable Development. In: Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, and T. Waterfield (eds.)]. https://www.ipcc.ch/site/assets/uploads/sites/2/2019/02/SR15_Chapter2_Low_Res.pdf

Ireland. (2023). Ireland's Long-term Strategy on Greenhouse Gas Emissions Reduction. Government of Ireland. https://unfccc.int/sites/default/files/resource/Ireland%20LTS.pdf?download

KfW. (2024). Klimafreundlicher Neubau im Niedrigpreissegment. Kreditanstalt für Wiederaufbau. https://www.kfw.de/PDF/Download-Center/F%C3%B6rderprogramme-(Inlandsf%C3%B6rderung)/PDF-Dokumente/6000005195_M_296.pdf

Maduta, C., D'Agostino, D., Tsemekidi Tzeiranaki, S., Castellazzi, L.,& Melica, G. & Bertoldi, P. (2023). Towards climate neutrality within the European Union: Assessment of the Energy Performance of Buildings Directive implementation in Member States. Energy and Buildings. 301. 113716. https://doi.org/10.1016/j.enbuild.2023.113716

Ramboll. (2022). Whole life carbon models for the EU27 to bring down embodied carbon emissions from new building: Review of existing national legislative measures. https://7520151.fs1.hubspotusercontent-na1.net/hubfs/7520151/RMC/Content/Whole-life-carbon-models-Review-of-national-legislative-measures.pdf

UK GBC. (2021). Net Zero Whole Life Carbon Roadmap: A Pathway to Net Zero for the UK Built Environment. UK Green Building Council. https://ukgbc.org/wp-content/uploads/2021/11/UKGBC-Whole-Life-Carbon-Roadmap-A-Pathway-to-Net-Zero.pdf

UNFCCC. (2021). Compendium on Greenhouse Gas Baselines and Monitoring: Building and Construction Sector. United Nations Framework Convention on Climate Change. https://unfccc.int/sites/default/files/resource/UNFCCC%20Compendium%20GhG%20Building%20Sector.pdf

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